Health: quotes, facts and reflections - Page 9

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WonderHealth

Clostridioides difficile, or C. diff, is a gut bacterium that can cause severe diarrhoea and may return after antibiotic treatment. Restoring healthy gut microbes can cut that risk: the US Food and Drug Administration (FDA) approved Rebyota, a faecal microbiota product given rectally, in 2022, and Vowst, an oral capsule, in 2023, to prevent recurrence in adults.

C. difficile tends to take hold when antibiotics wipe out the normal mix of gut microbes, and in serious cases it causes life-threatening inflammation of the colon. For years doctors restored that mix with faecal microbiota transplants, giving stool from screened donors by colonoscopy, enema or capsule. Screening varied, and in 2019 the FDA issued a warning after two patients were infected with drug-resistant bacteria from donor stool and one died. Rebyota and Vowst are made and tested to a fixed standard. Both are approved only to prevent another episode after antibiotic treatment, not to treat an active infection.

FDA approvals of Rebyota (2022) and Vowst (2023)Read card

WonderHealth

Catching up on sleep at the weekend did not undo the metabolic effects of short weeknights in a 2019 laboratory study. One group slept five hours a night; another had five short nights, two free weekend nights, then two more short nights. The weekend group still gained weight and lost insulin sensitivity, and some measures were worse.

The study, run in a sleep laboratory at the University of Colorado, mimicked a common real-life pattern: short sleep on workdays and extra sleep at the weekend. Insulin sensitivity measures how well the body responds to insulin, the hormone that clears sugar from the blood after eating; when it drops, blood sugar runs higher than it should, which over time raises the risk of type 2 diabetes. The recovery group did sleep in and snack less at night over the weekend, but those gains reversed as soon as short nights resumed, and some measures ended up worse than in the group that never got extra sleep. The findings challenge the popular idea that weekend lie-ins can cancel out a week of short sleep.

Depner et al., Current Biology, 2019Read card

WonderHealth

Blue-light-filtering glasses appear to do little or nothing for eye strain in the short term, according to a 2023 Cochrane review of 17 trials. Evidence on sleep was too uncertain for a firm conclusion, and none of the trials tested protection against damage to the retina.

A Cochrane review pools the results of many clinical trials under strict, published rules, and is widely treated as one of the most reliable kinds of medical evidence; Cochrane itself is an international network of researchers. This review combined 17 trials with 619 participants in six countries, but the trials were small and short, lasting from less than a day to five weeks. For eye strain, the tired, dry or aching eyes that come with long screen use, the authors rated the evidence as low certainty; on sleep, the trials disagreed and certainty was very low. They called for larger, longer trials.

Singh et al., Cochrane Systematic Review, 2023Read card

StillnessHealth

It is not difficult to make microbes resistant to penicillin in the laboratory by exposing them to concentrations not sufficient to kill them…

Alexander Fleming was the Scottish bacteriologist who noticed in 1928, at St Mary's Hospital in London, that a mould was killing the bacteria on one of his culture plates; the substance it made became penicillin. He shared the 1945 Nobel Prize with Howard Florey and Ernst Chain, who turned it into a usable drug. In his lecture he imagined a man who takes too little penicillin for a sore throat, breeds resistant bacteria and passes them to his wife, who then dies of an infection penicillin can no longer cure. Misuse of antibiotics is still a major cause of drug resistance.

Alexander Fleming, Nobel Lecture, 11 December 1945Read card

StillnessHealth

An apple a day keeps the doctor away.

The saying grew from a Welsh rhyme recorded in Pembrokeshire in 1866: eat an apple on going to bed, and you'll keep the doctor from earning his bread. The short modern form was in print by 1913, when the folklorist Elizabeth Mary Wright noted it in Rustic Speech and Folk-lore, alongside versions featuring onions. Apples do provide fibre and vitamin C, but a 2015 US study found that people who ate an apple a day visited the doctor about as often as everyone else.

Traditional proverb; recorded by Elizabeth Mary Wright, Rustic Speech and Folk-lore (1913)Read card

WonderTechnology

Wilson Greatbatch's implantable pacemaker began with a mistake: in 1956 the American engineer fitted the wrong resistor into a circuit, and it gave off regular electrical pulses, like a heartbeat. With the surgeon William Chardack he spent years turning it into a sealed device, first implanted in a patient in 1960.

A pacemaker sends small electrical pulses to the heart when its own rhythm is too slow or irregular. Early pacemakers were boxes outside the body, wired to the heart through the skin. Greatbatch, then at the University of Buffalo, tested his design in dogs with Chardack before the first human implant in Buffalo, New York, in 1960; that patient lived for a further 18 months. It was not the very first attempt: in Sweden in 1958, a pacemaker implanted in Arne Larsson failed after three hours. Early devices were sealed in epoxy resin and ran on mercury batteries that wore out quickly, so in 1971 Greatbatch developed a lithium-iodide battery that let pacemakers work for up to about ten years. It became the standard.

Wilson Greatbatch and William Chardack; device implanted in 1960Read card

WonderTechnology

Willem Kolff, a young Dutch doctor, built one of the first working artificial kidneys during the Nazi occupation of the Netherlands. Blood ran through cellophane tubing while waste passed through its thin wall into a surrounding fluid. His first 15 patients died; in 1945 a 67-year-old woman became the first to survive.

The treatment is called dialysis: when the kidneys fail, a machine cleans the blood in their place. Kolff worked in the small town of Kampen from 1941, building with whatever wartime shortages allowed: cellophane sausage casings wound around a rotating drum, orange-juice cans and car parts. Over two years he treated 15 patients, and all of them died before his 1945 success. After the war he sent machines to hospitals abroad. He moved to the United States in 1950 and worked at the Cleveland Clinic on dialysis and heart-lung machines. From 1967 he led artificial-organ research at the University of Utah, where the Jarvik-7 artificial heart was developed; its first patient, Barney Clark, lived for 112 days in 1982 and 1983.

Willem Kolff, 1943-1945, Kampen, NetherlandsRead card

WonderHistory

Onesimus, an African man enslaved in Boston, told the Puritan minister Cotton Mather how people in his homeland guarded against smallpox: they deliberately gave healthy people a small, controlled infection. During Boston's 1721 epidemic, Mather championed the method and the physician Zabdiel Boylston put it into practice.

The method, called variolation, put material from a smallpox sore into a small cut in a healthy person. It usually caused a milder illness and lasting immunity, though it could still kill; vaccination, which uses a different and safer virus, came later, in 1796. Mather had learned of it from Onesimus around 1716. When the epidemic struck in 1721, infecting about half of Boston's 11,000 people, Boylston first inoculated his six-year-old son and two enslaved men. The backlash was fierce: someone threw a lit explosive through Mather's window. Onesimus had already gained partial freedom in 1716 by paying for another enslaved man to take his place; little else is known of his life.

Historical account — Royal Society; U.S. National Park ServiceRead card

WonderHistory

In 1810, Sake Dean Mahomed opened London's Hindoostane Coffee House, an early Indian restaurant. The business failed, but he found a new trade in Brighton: massage and steam baths. His customers eventually included Kings George IV and William IV.

Mahomed was born in Patna, India, in 1759 and served for more than a decade in the East India Company's army, training as a surgeon. When his patron, Captain Godfrey Evan Baker, resigned in 1782, Mahomed left the army too and followed him to Ireland. In Cork he fell in love with Jane Daly; her family opposed the match, and the couple eloped to marry. In 1794 he published The Travels of Dean Mahomet, becoming the first Indian to publish a book in English. In Brighton he offered 'shampooing', from the Hindi champi, a therapeutic massage; the word only later came to mean washing hair. George IV and William IV each made him their 'shampooing surgeon'. He died in Brighton in 1851.

Historical account and collection — Royal College of Surgeons of EnglandRead card

WonderLanguage

Protactile is a way of communicating through touch, developed by DeafBlind people for one another. It began in Seattle in 2007, when three DeafBlind staff at the DeafBlind Service Center wanted to talk as a group without relying on interpreters, and began finding ways to converse directly on each other's hands, arms and bodies.

The three were aj granda, Jelica Nuccio and Jackie Engler. Protactile grew among people who, like many DeafBlind Americans, were born deaf, grew up with American Sign Language and lost their sight gradually, often through Usher syndrome, an inherited condition. Sign languages are built for the eyes: faces and signs made in the air carry much of the meaning. Protactile moves that information onto the body. A listener rests a hand on the speaker's arm or leg and taps to show 'yes' or 'I'm following', much as a nod would, and maps can be drawn on a hand or back. granda and Nuccio say they did not invent protactile: they set up events that put DeafBlind people in teaching roles, then named and documented what grew.

aj granda and Jelica Nuccio / Tactile Communications / Seattle DeafBlind communityRead card

WonderMind

In a 1996 study, the neuroscientist V.S. Ramachandran and Diane Rogers-Ramachandran placed a mirror so that the reflection of an amputee's intact hand appeared where the missing, “phantom” hand was still felt. Of five patients whose phantom hand felt painfully clenched, four said the mirror let them “open” it and eased the spasm.

Most people who lose a limb go on feeling it, a sensation called a phantom limb, and many feel pain in it, sometimes as if the missing hand were clenched with the nails digging in. Ramachandran, a neuroscientist at the University of California, San Diego, reasoned that the brain kept sending commands to the hand and getting no answer back. In the mirror box, a box with a mirror down the middle, the patient moves the intact hand and sees its reflection where the missing one should be; for a moment the brain accepts that the phantom is moving and relaxing. Mirror therapy is now also used after strokes and for a chronic pain condition called complex regional pain syndrome. Reviews find it helps some patients, though many trials are small.

V.S. Ramachandran & Diane Rogers-Ramachandran, 1996Read card

WonderMind

In a small 2026 study, 28 adults had eight sessions of training in sensing their own heartbeat, part of what scientists call interoception. Their heartbeat-perception scores improved and their self-reported everyday anxiety fell, compared with 26 people who received no training.

Interoception is the brain's sense of what is happening inside the body: heartbeat, breathing, hunger and similar signals. Some researchers think anxiety can be fed by misreading ordinary bodily changes, such as a faster heartbeat, so learning to read these signals more accurately might help. The study, by Chatrin Suksasilp and colleagues in the journal Biological Psychology, also used a statistical model of perception, which suggested that after training the participants' brains gave more weight to signals arriving from the heart. The comparison group simply had no training, so expectation or extra attention could explain part of the result, and a study this small cannot show that the training treats anxiety.

Chatrin Suksasilp et al., Biological Psychology (2026)Read card

WonderHealth

Around 1890 in the Dutch East Indies, now Indonesia, the Dutch doctor Christiaan Eijkman noticed that chickens fed polished white rice developed a nerve disease like beriberi. When the birds went back to unpolished rice, they recovered.

Beriberi damages the nerves and heart, and in the late 19th century it was a major, unexplained disease in Asian countries where polished white rice was the staple. Eijkman's discovery began by chance: his chickens were fed leftover white rice from the military hospital until a new manager refused to let hospital rice go to the birds, and once they were back on cheaper unpolished rice they got better. Eijkman first thought white rice held a poison or germ that the grain's outer layers neutralised. His successor, Gerrit Grijns, argued instead that polishing removed something the body needs. That substance is now known as thiamine, or vitamin B1. Eijkman shared the 1929 Nobel Prize in Physiology or Medicine with Frederick Hopkins.

Christiaan EijkmanRead card

WonderHealth

In 1943, scientists at a US Department of Agriculture laboratory in Peoria, Illinois, found a Penicillium mould on a mouldy cantaloupe melon that made far more of the antibiotic penicillin than the strains they had been using.

During the Second World War the Allies needed penicillin in huge amounts to treat infected wounds, but Alexander Fleming's original mould produced very little of it. At the Northern Regional Research Laboratory in Peoria, scientists had already raised yields by growing the mould in deep tanks fed with corn steep liquor, a by-product of maize processing, and they were testing moulds sent from around the world. The best one came from a melon bought at a Peoria market, usually credited to the laboratory assistant Mary Hunt. Treated with X-rays and ultraviolet light, its offspring produced far more still, and by the D-Day landings in June 1944 the United States could supply millions of doses. Most penicillin made today still comes from moulds descended from that melon.

USDA Northern Regional Research LaboratoryRead card

WonderHealth

Around 1890 at Johns Hopkins Hospital in Baltimore, the operating-theatre nurse Caroline Hampton developed a painful skin reaction to the mercuric chloride antiseptic used on her hands. The surgeon William Halsted asked the Goodyear Rubber Company to make thin rubber gloves for her, and his assistants soon wore them too.

The gloves began as protection for one person's skin, not as a way to stop infection. Hampton was the chief nurse in Halsted's operating theatre, and the two married in 1890. Other members of the team took up gloves over the following years, and in the late 1890s Halsted's resident surgeon Joseph Colt Bloodgood wore them routinely and reported fewer wound infections, which helped make gloved surgery standard. Halsted is often called a founder of modern American surgery: he introduced the radical mastectomy for breast cancer and created the first formal training programme for surgical residents in the United States, at Johns Hopkins.

Johns Hopkins history — Caroline Hampton & William HalstedRead card

WonderHealth

The Framingham Heart Study has followed three generations of families from one Massachusetts town since 1948. It began with 5,209 adults; their children and the children's spouses joined from 1971, and a third generation from 2002.

Before this study, many doctors treated high blood pressure as a normal, harmless part of growing older. By tracking the same people year after year, Framingham's researchers showed that high blood pressure, high cholesterol, smoking and lack of exercise each raised the chance of later heart disease, and the study's reports popularised the term “risk factor” for such measurable warning signs. The US National Heart, Lung, and Blood Institute has funded the study since it began, working with Boston University since 1971. It has produced more than 3,000 scientific papers and is one of the most cited long-term health studies ever run.

Framingham Heart StudyRead card

WonderHealth

At rest, a kilogram of skeletal muscle burns about 13 kilocalories a day, while a kilogram of body fat burns about 4.5, according to estimates for younger adults. That is a difference of about 8.5 kcal per kilogram. The figures describe tissue at rest, not energy used during exercise.

Muscle cells keep working even at rest, while fat cells mostly store energy. Swapping a kilogram of fat for a kilogram of muscle would therefore add only about 8.5 kilocalories (the “calories” on food labels) to a day's resting energy use, a tiny share of a typical daily need of around 2,000. The heavy users are the organs: per kilogram, the liver and brain burn roughly 200 to 240 kcal a day, and the heart and kidneys about 440. Together they make up only around 5 per cent of body weight, yet they account for well over half of the energy the body uses at rest. The figures come from work by the nutrition scientist Marinos Elia, later refined by Zimian Wang and colleagues.

Resting-energy-expenditure studies (Elia; Wang et al.)Read card

WonderHealth

The appendix may be a “safe house” for helpful gut bacteria, researchers at Duke University proposed in 2007. After severe diarrhoea flushes out the intestine, bacteria sheltering there could help to re-seed it.

Charles Darwin saw the appendix as a shrinking leftover of a larger digestive pouch that plant-eating ancestors needed, and for over a century it was treated as useless. The Duke team, led by the surgeon Randal Bollinger and the scientist William Parker, pointed out that the appendix is a narrow side pocket off the large intestine, lined with immune tissue and coated in a film of bacteria, and so well placed to keep a reserve away from the main flow. Some hospital studies have linked a missing appendix to more repeat infections with Clostridioides difficile, a bacterium that can cause severe diarrhoea after antibiotics, though others found no link. A 2013 study across mammals found that the appendix evolved independently at least 30 times and was rarely lost once it appeared, which suggests it is useful.

William Parker, R. Randal Bollinger et al., Duke University (2007)Read card

WonderHealth

On 16 October 1846 in Boston, the dentist William Morton gave ether to Gilbert Abbott so that the surgeon John Collins Warren could operate on a growth in his neck: the first public demonstration of surgical anaesthesia. Abbott moved and made sounds during the operation, and records differ on what he later said about pain.

The operating theatre, under the dome of Massachusetts General Hospital's original building, is still called the Ether Dome and can be visited. Morton gave the ether through a glass inhaler of his own design. When the operation ended, Warren is remembered as telling the watching doctors, “Gentlemen, this is no humbug.” A report published that November by the surgeon Henry Jacob Bigelow and a note added later to Abbott's hospital record both describe his reaction, and they do not agree. A Georgia doctor, Crawford Long, had used ether in an operation in 1842 but did not publish until 1849, so it was the Boston demonstration that spread the news of anaesthesia around the world within months.

Massachusetts General Hospital records; Henry Jacob Bigelow (1846)Read card

WonderHealth

The English physician William Harvey showed in 1628 that the heart pumps the same blood round the body in a circuit. In his book De Motu Cordis (On the Motion of the Heart), he used dissections, the valves in the veins and simple arithmetic: the heart moves far more blood than food could ever replace.

Harvey's key argument was a calculation. Taking deliberately low figures for how much blood each heartbeat pushes out, he showed that within half an hour the heart moves more blood than the whole body contains, so the same blood must keep coming back. The one-way valves in the veins, described by his teacher Fabricius in Padua, let blood flow only towards the heart. Harvey was physician to King James I and then to Charles I, and stayed loyal to the Crown in the Civil War. He could not see the tiny vessels linking arteries to veins; Marcello Malpighi found these capillaries under a microscope in 1661, four years after Harvey's death.

William Harvey, De Motu Cordis (1628)Read card

WonderHealth

Guinea worm disease, a painful parasitic infection, struck an estimated 3.5 million people a year in 21 countries when the global campaign against it began in 1986. In January 2026, the Carter Center reported a provisional 10 human cases for 2025, a fall achieved without any vaccine or curative drug.

The disease starts when someone drinks water containing tiny water fleas that carry the parasite's larvae. Inside the body the worm grows for about a year, reaching up to a metre in length, then breaks out through a painful blister, usually on the leg or foot, and can leave a person unable to work for weeks. With no vaccine or cure, the campaign has relied on filtering drinking water, treating ponds with larvicide and keeping people with emerging worms out of water sources. Former US President Jimmy Carter, who died in 2024, led the Carter Center's campaign from the start. The Center still works in six African countries: Angola, Cameroon, Chad, Ethiopia, Mali and South Sudan. Infections in animals, especially dogs in Chad, now make the last stretch harder.

The Carter Center (Guinea Worm Eradication Program)Read card

WonderHealth

In 1858, Florence Nightingale published a circular mortality diagram from the Crimean War. Blue areas showed deaths from preventable disease, red from wounds and black from other causes. The blue overwhelmed the red: far more British soldiers were dying from disease than from battle wounds.

The diagram covered April 1854 to March 1856 month by month, and it showed deaths from disease falling sharply once sanitary conditions improved. Nightingale had led the nurses at the British army's hospital in Scutari, housed in the Selimiye Barracks in today's Üsküdar, Istanbul. She used this kind of chart, now often called a polar area or “rose” diagram, to make a point that plain tables could not: disease, not the enemy, was killing most of the soldiers. After the war she campaigned to reform army medicine and hygiene, and in 1858 she became the first female member of the Statistical Society of London, now the Royal Statistical Society.

Florence Nightingale, Crimean War mortality statistics, 1858Read card